package com.example.blog.utils;

import com.example.blog.Constants.Constants;
import io.jsonwebtoken.Claims;
import io.jsonwebtoken.JwtParser;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.io.Decoders;
import io.jsonwebtoken.security.Keys;
import lombok.extern.slf4j.Slf4j;

import java.security.Key;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

@Slf4j
public class JwtUtils {
    private static final long JWT_EXPIRATION = 60 * 60 * 1000 *2;
    //拿到后再生成key
    private static final String secreStr = "Q+06k4nEp9NyC9RDjWS9u4yIzYAxid816YysQg4nynU=";
    private static final Key key = Keys.hmacShaKeyFor(Decoders.BASE64.decode(secreStr));
    //生成token
    public static String genJwtToken(Map<String,Object> claim){

        String token = Jwts.builder().setClaims(claim)
                .setExpiration(new Date(System.currentTimeMillis()+JWT_EXPIRATION))//设置过期时间
                .signWith(key)//设置签名
                .compact();
        return token;
    }


    //校验token
    //claims为null校验失败
    public static Claims parseToken(String token){
        //解析token
        JwtParser build = Jwts.parserBuilder().setSigningKey(key).build();
        Claims claims = null;
        try {
           claims = build.parseClaimsJws(token).getBody();
        }catch (Exception e){
            log.error("解析token失败，token：{}",token);
            return null;
        }
        return claims;
    }

    //从token中获取ID
    public static Integer getIdByToken(String token){
        Claims claims = parseToken(token);
        if (claims!=null){
            Integer UserId =(Integer) claims.get(Constants.TOKEN_ID);
            if (UserId > 0){
                return UserId;
            }
        }
        return null;
    }
}
